KR0128366B1 - Liquid crystal display device - Google Patents

Abstract

The present invention provides an active matrix type liquid crystal display device of a normal white mode which can easily flicker a bright-point-defective pixel, wherein the matrix-arranged pixel electrode 4a and each pixel electrode 4 driven and controlled by an address signal are provided. A matrix array substrate 13 composed of a TFT 3 provided in the upper and lower portions of the pixel electrodes 4 and a bus line 9 and 10 to which a predetermined voltage is provided through the insulating layer 11. Opposing substrate 7 having liquid crystal layer 8 provided on array substrate 13 and corresponding electrode 7 corresponding to pixel electrode 4 and sandwiching liquid crystal layer 8 together with matrix array substrate 13. In the pixel electrode 4, the bright point defect is short-circuited with the bus line 9 so that the voltage of the bus line 9 is applied.

Description

LCD Display

1 is a diagram showing a typical equivalent circuit of a liquid crystal display device according to a first embodiment of the present invention.

2 is a plan view of one pixel of the liquid crystal display of FIG.

3 is an A-A cross-sectional view of the pixel of FIG.

4 shows waveforms of bias voltages.

5 is a plan view of one pixel of the liquid crystal display device according to the second embodiment of the present invention.

6 is a plan view of one pixel of the liquid crystal display device according to the third embodiment of the present invention.

7 is a plan view of one pixel of the liquid crystal display device according to the fourth embodiment.

8 is a plan view of one pixel of the liquid crystal display device according to the fifth embodiment of the present invention.

9 is a diagram for explaining the connection between a TFT and a pixel electrode.

10 is an equivalent circuit of a conventional active matrix liquid crystal display device.

* Explanation of symbols for main parts of the drawings

1: address line, 2: data line,

3,3a, 3b, 3c, 3d, 3e, 3f: TFT, 4: transparent pixel electrode,

5,6 storage capacitor, 7 counter electrode,

8: liquid crystal layer, 9, 9a, 9b, 10, 10a, 10b: bus line,

11: insulating film, 12: electrode wiring,

13: matrix array substrate, 14: counter substrate,

16: laser light

The present invention relates to a liquid crystal display device, and more particularly, to an active matrix liquid crystal display device of a normal white mode.

BACKGROUND ART Liquid crystal displays have the characteristics of being thin, lightweight, low voltage drive, easy to color, and have recently been used as display devices for personal computers and word processes.

Among them, the so-called active matrix type liquid crystal display device, in which switching elements are provided for each pixel, is capable of intermediate display without deterioration of contrast and response even with a large number of pixels. to be.

10 is an equivalent circuit of a conventional active matrix liquid crystal display device using a thin film transistor (TFT) as a switching element.

The liquid crystal display device is broadly divided into two substrates (array substrates and opposing substrates) made of a transparent insulating material such as glass, and a liquid crystal layer 8 sandwiched by these substrates.

On the array substrate, pixels consisting of TFTs 3 and transparent electrode pixels 4 are provided in a matrix.

The address line 1, the transparent pixel electrode 4, and the data line 2 are connected to the gate, the source, and the drain of the TFT 3, respectively.

The opposing substrate is provided with an opposing electrode 7 provided relatively to the transparent pixel electrode 4.

In the liquid crystal display device configured as described above, a voltage corresponding to the display can be selectively applied to each pixel electrode 4 by applying address signals and data signals to the address line 1 and the data line 2 at predetermined timings. have.

The alignment of the liquid crystal layer 8, that is, the light transmittance, can be controlled by the potential difference between the counter electrode 7 and the pixel electrode 4, thereby enabling arbitrary display.

Generally used liquid crystal is a twist nematic mode (polarizer) is provided on the outside of both organs, respectively.

According to the orientation direction of this polarizing plate, two types of display modes, a normal white mode and a normal black mode, can be realized.

That is, the normal white mode is the case where the light transmittance when the voltage is not applied to the liquid crystal layer 8 is the maximum, and the normal black mode is the case where the maximum light transmittance is the maximum.

In normal black mode, normal white is usually difficult to achieve due to the fact that the thickness of the liquid crystal layer slightly deviates, the minimum light transmittance is irregular, and the optimal liquid crystal layer is different depending on the wavelength of light transmitted therethrough. Mode is used a lot.

However, since the manufacturing process of the switching element starting from the TFT is very complicated, it is very difficult to produce all the pixels without defects, and some defective pixels are also included in the product level.

There are several kinds of defective pixels, but the most lost display quality is the bright spot defect pixels that appear bright when the pixel is displayed in a lump.

In the liquid crystal display device of the normal white mode, the bright point defect is basically caused when a voltage sufficient to change the light transmittance of the liquid crystal layer is not applied to the pixel electrode.

Since there are many reasons for this, the use of various types of overly long structures, etc., could not eliminate all of these bright pixels.

As described above, the active matrix liquid crystal display device of the normal white mode has a problem in that the display quality is remarkably lowered because the defect pixels in the form of bright spots are included.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display device capable of converting a bright spot defect pixel into a black spot defect that is hardly noticeable in pixel defects. do.

The gist of the present invention is to provide a bus line to which a predetermined voltage connectable to the pixel electrode is applied and to compensate for the drop in the voltage of the liquid crystal layer caused by the drop in the pixel electrode by the voltage of the bus line.

That is, in order to achieve the above object, the liquid crystal display device of the present invention has a matrix-managed pixel electrode, a switching element provided in each pixel electrode driven and controlled by an address signal, and an insulating layer provided under each pixel electrode. A counter array substrate having a matrix array substrate comprising a bus line to which a predetermined voltage is applied, a liquid crystal layer provided on the matrix array substrate, and a counter electrode corresponding to the pixel electrode, and sandwiching the liquid crystal layer together with the matrix array substrate. And a bright point defect in the pixel electrode is short-circuited with the bus line and the voltage of the bus line is applied.

The bus line may include a first bus line and a second bus line to which an AC voltage having a reverse phase is applied, and a voltage applied to the first bus line is V ₁ , the bus line and the pixel electrode. when the voltage applied to the capacitance between the bus line C _1, the second and the capacitance between the V _2, the bus line and the pixel electrode to the C ₂ C _1, the value of V ₁ and C _2, It is appropriate that the values of V ₂ are about the same.

According to the liquid crystal display device of the present invention, the voltage drop of the pixel electrode can be compensated for by shorting one bus line and the pixel electrode when the voltage of the pixel electrode is reduced.

At this time, if the voltage of the bus line is set so that the voltage of the compensated pixel electrode is at a level sufficient to lower the light transmittance of the liquid crystal layer, the bright point defective pixel can be converted into a no defective defect pixel.

In addition, if the pulse voltage of the reverse phase is applied to the two bus lines, and the values of C ₁ , V _{l and} the value of C ₂ V ₂ are approximately equal, the influence of the voltages of the two bus lines in the normal operation is affected by the display pixel electrode. The indications are not affected by the voltages on these bus lines since they are mutually negated.

Which each have a charge Q ₂ accumulated in the electric charge Q ₁ and the capacitor C ₂ stored in the capacitor C ₁ by a pulse voltage _{Q 1 = C 1 · V 1} , Q 1 = C 2 · V 2 is also a pulse voltage is reverse This is because the charge? Q induced by the pulse voltage of the reverse phase in the pixel electrode becomes? Q = Q ₁ + Q ₂ = Q because of the phase.

Embodiments will be described below with reference to the drawings.

1 is a schematic equivalent circuit of a liquid crystal display device according to a first embodiment of the present invention, FIG. 2 is a plan view of one pixel of the liquid crystal display device of FIG. 1, and FIG. 3 is an A-A cross-sectional view of the pixel of FIG.

The liquid crystal display device is roughly divided into two substrates made of a transparent insulating material such as glass, that is, a matrix array substrate 13, an opposing substrate 14, and a liquid crystal layer 8 sandwiched by these substrates 13 and 14. Is done.

In one pixel of the liquid crystal display, a gate is connected to the address line 1, one source and a drain are connected to the pixel electrode 4 through the connection line 12, and the other source and the drain are data lines. It is formed on the TFT 3 connected to the (2) and the storage lines 5 and 6 formed on the bus lines 9 and 10 and connected to the pixel electrode 4 via the insulating film 11.

The TFT 3 is a reverse staggered TFT in which a gate portion is formed below the active layer 15 through the insulating film 11.

Amorphous silicon is used as the material of the active layer 15.

In addition, a channel protective film 16 is provided on the active layer 15 so that the active layer 15 is not damaged during the manufacturing process.

ITO (Indium Tin Oxide) is used as the material of the pixel electrode 4.

The capacitances Ca ₁ and Ca ₂ of the storage capacitors 5 and 6 are all the same 0.15 pF.

The bus lines 9 and 10 are made of an alloy thin film of molybdenum and tantalum, and the width of each is 15 mu m. These bus lines 9 and 10 are made of an alloy thin film of molybdenum and tantalum, each having a width of 15 µm galti.

These bus lines 9 and 10 have mutually reversed bias voltages V _B1 having 5 [V] in the center voltage V _com , 4 [V] in the amplitudes V ₁ and V ₂ , and 180 ° out of phase, as shown in FIG. 4. , V _B2 is connected.

The periods of these bias voltages V _B1 and V _B2 are all 30 Hz, which is about half of the period required to select one pixel of the liquid crystal display device, that is, each address line 1 once.

The amplitudes V ₁ and V ₂ of the bias voltages V _B1 and V _B2 may not be 4 [V] if the transmittance of the liquid crystal is larger than the voltage at which the liquid crystals start to change.

The data line 2 has a pulse signal voltage having a center voltage of 6 [V], a width of V _sig [V], and a period of 30 Hz, that is, one screen is positive and the next one is negative. Is a voltage that can drive.

In addition, the potential V _com of the counter electrode 7 is set to [V] and adjusted so that a direct current voltage is not applied to the liquid crystal layer 8.

Next, the operation in the normal operation of the liquid crystal display device configured as described above will be described.

When a data signal of 6 ± V _sig [V] is applied to the data line 2, a selection pulse voltage is applied to the address line 1 at this time, and thus the data signal is applied to the pixel electrode 4 through the TFT 3. Is applied.

When the selection pulse voltage is off (off), switching noise DELTA Vp occurs in the TFT 3 and the pixel electrode potential Vp shifts.

Since the switching noise ΔVp of the TFT 3 is about 1 [V], the voltage held at the pixel electrode 4 eventually becomes 5 ± V _sig (6 ± V _sig −1) [V].

The bias voltages V _B1 and V _B2 are 18 degrees out of phase and satisfy the following equation (1).

_{C S1 · V 1 = C S2} · V S2 ························ (1)

As a result, the influence of these bias voltages V _B1 and V _B2 is negated in the pixel electrode potential Vp and is not affected by this charging operation.

Therefore, a voltage corresponding to the difference between the potential of the counter electrode 7 and the pixel electrode potential Vp, that is, ± V _s [V], can be applied to the liquid crystal layer 8, and accordingly, the light transmittance of the liquid crystal layer 8 is conventionally adjusted. It can be controlled and the desired display can be realized.

Next, the repair of the bright point defect pixel of the liquid crystal display device comprised next is demonstrated.

Here, the connection wiring 12 is disconnected, and no bright spot defect pixel is generated without applying a voltage to the pixel electrode 4.

First, the laser beam 15, for example, YAG laser light, is irradiated from the rear surface of the array substrate 13, and the bus line 9 and the pixel electrode 4 are short-circuited.

As a result, since the pixel electrode potential Vp is equal to the bias voltage V _B1 , a pulse voltage of 5 ± 4 V [V] is always applied to the pixel electrode 4.

Since the potential V _com ″ of the counter electrode 7 is 5 [V], a pulse voltage of ± 4 [V] is applied to the liquid crystal layer 8 substantially.

Since the maximum light transmittance at 0 [V] of the liquid crystal layer 8 is about 1%, this bright spot defect pixel becomes a dark spot defect pixel.

In addition, even that does not conform to the bias voltage V _B1, V _B2 can be formula (1) of the bus lines 9 and 10 in the normal display operation by the capacity existing in the liquid crystal layer 8, but these bias voltage V _B1 When the center voltages V _com, and the amplitudes V ₁ and V ₂ of V _B2 have adjustable functions, respectively, the DC component that causes deterioration of image quality can be removed from the normal pixel.

Moreover, even if some DC component is applied to the dark spot defect pixel, if a light transmittance is low enough, practically no problem will arise.

As described above, according to the present embodiment, in the normal white mode liquid crystal display, the bright defect pixel having the most adverse effect on the display quality can be simply converted to the small defect defect pixel.

In addition, since this defective pixel is alternatingly driven, there is no problem that the liquid crystal deteriorates by this repair.

5 is a plan view of one pixel of the liquid crystal display device according to the second embodiment of the present invention.

In addition, the same code | symbol as FIG. 1 is substituted in the part corresponding to the pixel of FIG. 2, and detailed description is abbreviate | omitted.

The liquid crystal display device of this embodiment differs from that of the first embodiment in that the widths of the bus lines 9 and 10 are different from each other.

That is, the widths of the bus lines 9 and 10 are 10 μm and 20 μm, respectively, and the capacitances C s ₁ and C s ₂ of the storage capacitors 5 and 6 are 0.1 pF and 0.2 pF, respectively.

In addition, pulse lines having an amplitude of 5.0 ± 5.0 [V] and a period of 30 Hz are applied to the bus line 9 in reverse phase.

Therefore, the condition of Equation (1) is satisfied, and the present embodiment has the same shape as in the previous embodiment, and there is no problem in the normal display operation.

In the same manner as in the previous embodiment, the storage capacitor 5 and the pixel electrode 4 were short-circuited by irradiation of YAG laser light on the substrate surface, and 5.0 ± 5.0 [ A voltage of V] is applied to convert the bright-point pixel into a dark-point pixel.

By setting the capacitors C s ₁ and C s ₂ to different values as in the present embodiment, the amplitude of the pulse voltage applied to the bus line 10 in which the storage capacitor is larger can be reduced.

In addition, a bus voltage 9 is applied to the bus line 9 to make the flash point flicker.

6 is a plan view of one pixel of the liquid crystal display device according to the third embodiment of the present invention.

In addition, the part corresponding to the pixel of FIG. 2 replaces the same code | symbol as FIG. 1, and detailed description is abbreviate | omitted.

The liquid crystal display of this embodiment differs from that of the first embodiment in that a plurality of pixel electrodes are provided in one pixel.

That is, the two pixels are divided into two, and switching transistors 3a and 3b and pixel electrodes 4a and 4b are provided in each.

Bus lines 9a and 9b and bus lines 10a and 10b are respectively disposed below the pixel electrodes 4a and 4b.

The wiring width of the bus lines 9a and 9b is 15 m, and the width overlapping with the bus line 10a and the pixel electrode 4a and the width overlapping with the bus line 10b and the pixel electrode 4b are 15 m.

The bus lines 10a and 10b also serve as bus lines of sub-pixels of adjacent pixels.

Bus lines 9a, 10a, 9b and 10b are applied with a busline voltage having an amplitude of 50 ± 4 [V] and a period of 30 Hz.

The phase relationship of the bias voltages applied to these bus lines 9a, 10a, 9b and 10b is inversely opposite to the bus lines 9a, 9b, 10a and 10b as in the previous embodiment. It is.

In each sub-pixel, the same common signal is all the same process and is independently applied to each of the pixel electrodes 4a and 4b.

In addition, the potential of the counter electrode 7 is set to about 5 [V].

The repair of the bright spot defective pixel may be performed by shorting the bus line and the pixel electrode of the bright spot defective pixel by using a laser in the same manner as in the previous embodiment.

Since bright spot defects rarely occur randomly, there are few points where two subpixels of the same pixel become bright spot defects together.

Therefore, in most cases, the repair of the bright spot defective pixel only erases one of the subpixels, so that the same display as that of the normal pixel can be realized even if the brightness is reduced by half by the flashing.

7 is a plan view of one pixel of the liquid crystal display device according to the fourth embodiment of the present invention.

In addition, the same code | symbol is substituted for the part corresponding to the pixel of FIG. 4, and detailed description is abbreviate | omitted.

In the third embodiment, the bus lines 10a and 10b are made common between adjacent sub-pixels, and the overlap with the pixel electrodes is set so as to be equal to the capacitance by the bus lines 9a and 9b.

However, the manufacturing process of the TFT array, if there is a language baereonseu the capacitor C _s1, C _s2 scratches caused by alignment of the mask.

The width of the bus lines 101 and 91 of the sub-pixel 41 and the bus lines 102 and 92 of the adjacent sub-pixels in the liquid crystal display of the present embodiment is reduced so that the unbalance of capacitance is small even with such a mask scratch. Alternatively, the bus line 101 and the bus line 102 are connected to each other by the bypass 103 so as to be electrically connected even if the area is the same and the same reference numerals are added to the bus lines 101 and 102.

When the bypass 103 is sufficiently thin, the unbalance of the capacitance of the storage capacitors 51, 52, 61, and 62 due to the mask scratch can be eliminated, and when the bus lines 101 and 102 are disconnected, Also, it is possible to apply a predetermined signal.

8 is a schematic circuit diagram of one pixel of the liquid crystal display device according to the fifth embodiment of the present invention.

In addition, the same code | symbol as FIG. 4 is substituted for the part corresponding to the pixel of FIG. 3, and detailed description is abbreviate | omitted.

As one of the causes of the bright point defect pixel, there is a decrease in the pixel potential due to a poor characteristic of the TFT.

The distinction between a bad TFT and a normal TFT is difficult to judge in appearance, driving, and the like.

For this reason, it is generally difficult to distinguish between bright spot defective pixels due to TFT defects and bright spot defective pixels due to poor connection of wiring.

The liquid crystal display device of this embodiment can easily distinguish between the causes of these two bright spot defects and can be appropriately repaired according to the causes.

In other words, the liquid crystal display of this embodiment differs from that of the third embodiment in that two TFTs are provided in each sub-pixel.

The TFT 3d and the TFT 3c are provided in the pixel electrode 4a.

The TFT 3d is electrically connected to the pixel electrode 4a.

The TFT 3c is connected to the pixel electrode 4a via the connection wiring 20 and is not normally electrically connected.

That is, as shown in FIG. 9, the wiring 21 entangled in the TFT 3c and the wiring 23 entangled in the pixel electrode 4a are entangled in the connection wiring 22 through the insulating film 11.

In the same manner, the TFT 3e and the TFT 3f are provided in the pixel electrode 4b.

In the liquid crystal display device configured as described above, the bright point defect pixel is repaired as follows.

Here, the repair of the bright point defect pixel caused by the voltage drop of the pixel electrode 4b will be described.

First, the wiring 24 connecting the TFT 3d and the pixel electrode 4a is cut using a laser, and it is visually determined whether the voltage of the pixel potential 4a has decreased due to the characteristic defect of the TFT 3d. do.

If the bright point defect is caused by the TFT 3d, the laser light is irradiated from the back side of the substrate 13, and the wiring 21, the connection wiring 20, and the connection wiring 20 and the wiring 23 are connected and the TFT 3c is connected. The voltage of the pixel electrode 4a is controlled.

In the case where the bright point defect is not caused by the TFT 3d or when the bright point defect occurs even when the TFT 3c and the pixel electrode 4a are connected, two or one of the storage capacitors 5a and 6a may be used with a laser. It is good to connect to the pixel electrode 4a, and to perform a darkening.

In addition, when two bus lines need to be applied with mutually reversed pulse voltages, but there is no need for flashing, for example, when none of the flaw defect elements are present, two bus lines 9a and 10a have a predetermined value. DC voltage may be applied.

As a result, power consumption can be reduced.

In addition, if the cause of the bright spot defect is an electrical short circuit of the storage capacitor due to the pinhole of the insulating film under the storage capacitor, there is an advantage that it is automatically flickered without performing the repair by the laser irradiation described above.

As described above, according to the present embodiment, it is possible to repair the bright point defect pixel due to the poor connection of the wiring, and the point defect pixel due to the TFT characteristic defect can be easily repaired.

In addition, this invention is not limited to the above-mentioned embodiment.

For example, in the above embodiment, the driving method in which the counter electrode potential is made constant has been described, but the present invention can also be applied to the driving method in which the counter electrode potential is changed every scan line or every frame.

In this case, in addition to the change in the counter electrode potential, the pixel electrode potential due to the reverse phase pulses of the two bus lines may be modulated so that the effect is the same as that of one bus line.

That is, the amplitude and center voltage of the pulse voltage may be set so that the pulse bias does not affect the two bus lines when the signal voltage is 0 [V].

In the above embodiment, the case of a black and white display has been described, but the present invention can also be applied to a color display using a color filter.

In this case, since one pixel is formed of each unit pixel of red, blue, and green, unit pixels other than the defective unit pixel may be flickered in the division of each pixel as in the third embodiment.

In other words, if only the defective unit pixels are repaired, the color balance may be degraded and the display quality may be degraded. As a result, normal sub-pixels may be flickered as necessary, and the display quality may be prevented from being restored.

The present invention can also be applied to a liquid crystal display device using a three-terminal switching element and a two-terminal switching element other than a TFT.

Other modifications can be made without departing from the spirit of the invention.

As described above, according to the present invention, in the liquid crystal display device of the normal white mode, it is possible to easily convert bright spot defect pixels which have the most adverse effect on the display quality into dark spot defect pixels having less adverse effects.

Claims (14)

A matrix array substrate, an opposing substrate, a liquid crystal layer positioned between the matrix array substrate and the opposing substrate, an opposing electrode positioned between the opposing substrate and the liquid crystal layer, the matrix array substrate and the liquid crystal layer to correspond to a plurality of pixels A plurality of pixel electrodes positioned in between, a plurality of switching elements respectively connected to the plurality of pixel electrodes, transmission means for transmitting an address signal to the plurality of switching elements for driving the plurality of switching elements, the plurality of pixel electrodes First and second bus lines configured to correspond to the plurality of pixel electrodes, the first and second bus lines having portions facing the plurality of pixel electrodes through the insulating layer, and first voltage applying means for applying a first voltage to the first bus lines. A second voltage applying means for applying a second voltage to the pixel electrode corresponding to the defective portion of the first bus line and a defective pixel; And a short circuit means for connecting, wherein the first voltage and the second voltage are out of phase with each other and satisfy C ₁ · V ₁ = C ₂ · V ₂ , wherein V ₁ and V ₂ are the first and the _second voltages. The magnitudes of the two voltages, C ₁ and C _2, represent the capacitance between the opposite portions of the first bus line and the pixel electrode and the capacitance between the opposite portions of the second bus line and the pixel electrode. An activated matrix liquid crystal display device of a normal white mode having a plurality of pixels including a defect pixel indicating a defect. The method of claim 1, wherein the first and second voltages are AC voltages having a 180 ° difference therebetween, satisfying the formula C ₁ · V ₁ = C ₂ · V ₂ , wherein V ₁ and V ₂ are described above. An active matrix liquid crystal display device of a normal white mode, characterized by showing first and second voltages. The normal white mode of claim 1, wherein the first bus line and the insulating layer are formed of a material melted by a laser beam, and the short circuit means is formed of a melt of a portion of the first bus line. Active matrix liquid crystal display device. The method of claim 1, wherein the first said opposing portions of the bus line had a width narrower than said opposed portion of the second bus lines, active in the normally white mode, characterized in that C _s1 C _s2, and the V ₁ V _2, Matrix liquid crystal display device. The active matrix liquid crystal display device according to claim 1, wherein the plurality of pixels have a plurality of subpixels each having one pixel electrode. 6. The method of claim 5, wherein the second bus line has a width sufficient to overlap two adjacent pixels, and opposite portions corresponding to pixel electrodes of the two adjacent pixels are formed on both sides of the second bus line. An active matrix liquid crystal display device in a normal white mode. 6. The active matrix of the normal white mode according to claim 5, wherein an opposite portion of the second bus line corresponding to the pixel electrodes of the two adjacent pixels is vertically connected to the second bus line by one line. Type liquid crystal display device. A matrix array substrate, an opposing substrate, a liquid crystal layer positioned between the matrix array substrate and the opposing substrate, an opposing electrode positioned between the opposing substrate and the liquid crystal layer, the matrix array substrate and the liquid crystal layer to correspond to a plurality of pixels A plurality of pixel electrodes positioned in between, a plurality of switching elements respectively connected to the plurality of pixel electrodes, transmission means for transmitting an address signal to the plurality of switching elements for driving the plurality of switching elements, the plurality of pixel electrodes First and second bus lines configured to correspond to the plurality of pixel electrodes, the first and second bus lines having portions opposing the plurality of pixel electrodes through the insulating layer, the first voltage applying means for applying a first voltage to the first bus lines, and the second bus lines. A second voltage applying means for applying a second voltage to the first voltage, the first voltage and the second voltage being out of phase with each other, and C _1; V _{01 =} C ₂ V | ₂ , wherein V ₁ and V ₂ are magnitudes of the first and second voltages, and C ₁ and C ₂ are capacitances between the opposing portion of the first bus line and the pixel electrode and the second bus line. An active matrix liquid crystal display device of a normal white mode having a plurality of pixels, characterized in that it represents a capacitance between an opposite portion and the pixel electrode. 9. The method of claim 8, wherein the first and second voltages are alternating current voltages 180 degrees out of phase with each other, satisfying the formula C ₁ · V ₁ = C ₂ · V ₂ , where V ₁ V | ₂ denotes the first and second voltages, wherein the active matrix liquid crystal display device of the normal white mode. 10. The liquid crystal display of claim 8, wherein the first bus line and the insulating layer are formed of a material melted by a laser beam. The method of claim 8, wherein the first said opposing portions of the bus line had a width narrower than said opposed portion of the second bus lines, active in the normally white mode, characterized in that C _s1 C _s2, and the V ₁ V _2, Matrix liquid crystal display device. 10. The liquid crystal display of claim 8, wherein the plurality of pixels include a plurality of subpixels each having one pixel electrode. 13. The method of claim 12, wherein the second bus line has a width sufficient to overlap two adjacent pixels, and opposite portions corresponding to pixel electrodes of the two adjacent pixels are formed on both sides of the second bus line. An active matrix liquid crystal display device in a normal white mode. The active matrix of the normal white mode according to claim 12, wherein an opposite portion of the second bus line corresponding to the pixel electrodes of the two adjacent pixels is vertically connected to the second bus line by one line. Type liquid crystal display device.